using System.Linq;
using Swashbuckle.AspNetCore.Swagger;
using Swashbuckle.AspNetCore.SwaggerGen;

namespace NetCoreKit.Infrastructure.AspNetCore.OpenApi
{
    /// <summary>
    ///     Represents the Swagger/Swashbuckle operation filter used to document the implicit API version parameter.
    /// </summary>
    /// <remarks>
    ///     This <see cref="IOperationFilter" /> is only required due to bugs in the <see cref="SwaggerGenerator" />.
    ///     Once they are fixed and published, this class can be removed.
    /// </remarks>
    public class DefaultValuesOperationFilter : IOperationFilter
    {
        /// <summary>
        ///     Applies the filter to the specified operation using the given context.
        /// </summary>
        /// <param name="operation">The operation to apply the filter to.</param>
        /// <param name="context">The current operation filter context.</param>
        public void Apply(Operation operation, OperationFilterContext context)
        {
            if (operation.Parameters == null) return;

            // REF: https://github.com/domaindrivendev/Swashbuckle.AspNetCore/issues/412
            // REF: https://github.com/domaindrivendev/Swashbuckle.AspNetCore/pull/413
            foreach (var parameter in operation.Parameters.OfType<NonBodyParameter>())
            {
                var description = context.ApiDescription.ParameterDescriptions.First(p => p.Name == parameter.Name);
                var routeInfo = description.RouteInfo;

                if (parameter.Description == null) parameter.Description = description.ModelMetadata?.Description;

                if (routeInfo == null) continue;

                if (parameter.Default == null) parameter.Default = routeInfo.DefaultValue;

                parameter.Required |= !routeInfo.IsOptional;
            }
        }
    }
}
